[AIX] Use less than or equal to for some alignment tests on AIX

[ZarkoCA]

Summary

On AIX the alignment implementation has the storage aligned to the
preferred alignment instead of the alignment of a type. Macro guard
these tests for AIX and have them pass when the "reference alignment" is
less than or equal to the alignment observed. In other words, the
alignment applied is at least as strict as the required alignment.

[hubert.reinterpretcast]

LGTM, but please note the adjustment to the description.

llvm/unittests/Support/AlignOfTest.cpp

TEST(AlignOfTest, BasicAlignedArray) {
   // that of the fundamental type and hope that we have any weird type
   // productions that would trigger bugs.
   EXPECT_EQ(alignof(T<char>), alignof(AlignedCharArrayUnion<char>));
   EXPECT_EQ(alignof(T<short>), alignof(AlignedCharArrayUnion<short>));
   EXPECT_EQ(alignof(T<int>), alignof(AlignedCharArrayUnion<int>));
   EXPECT_EQ(alignof(T<long>), alignof(AlignedCharArrayUnion<long>));
   EXPECT_EQ(alignof(T<long long>), alignof(AlignedCharArrayUnion<long long>));
   EXPECT_EQ(alignof(T<float>), alignof(AlignedCharArrayUnion<float>));
+#ifdef _AIX
+  EXPECT_LE(alignof(T<double>), alignof(AlignedCharArrayUnion<double>));
+  EXPECT_LE(alignof(T<long double>),
+            alignof(AlignedCharArrayUnion<long double>));
+  EXPECT_LE(alignof(S4), alignof(AlignedCharArrayUnion<S4>));
+#else
   EXPECT_EQ(alignof(T<double>), alignof(AlignedCharArrayUnion<double>));
   EXPECT_EQ(alignof(T<long double>),
             alignof(AlignedCharArrayUnion<long double>));
+  EXPECT_EQ(alignof(S4), alignof(AlignedCharArrayUnion<S4>));
+#endif
   EXPECT_EQ(alignof(T<void *>), alignof(AlignedCharArrayUnion<void *>));
   EXPECT_EQ(alignof(T<int *>), alignof(AlignedCharArrayUnion<int *>));
   EXPECT_EQ(alignof(T<double (*)(double)>),
             alignof(AlignedCharArrayUnion<double (*)(double)>));
   EXPECT_EQ(alignof(T<double (S6::*)()>),
             alignof(AlignedCharArrayUnion<double (S6::*)()>));
   EXPECT_EQ(alignof(S1), alignof(AlignedCharArrayUnion<S1>));
   EXPECT_EQ(alignof(S2), alignof(AlignedCharArrayUnion<S2>));
   EXPECT_EQ(alignof(S3), alignof(AlignedCharArrayUnion<S3>));
-  EXPECT_EQ(alignof(S4), alignof(AlignedCharArrayUnion<S4>));
   EXPECT_EQ(alignof(S5), alignof(AlignedCharArrayUnion<S5>));
   EXPECT_EQ(alignof(S6), alignof(AlignedCharArrayUnion<S6>));
   EXPECT_EQ(alignof(D1), alignof(AlignedCharArrayUnion<D1>));
   EXPECT_EQ(alignof(D2), alignof(AlignedCharArrayUnion<D2>));
   EXPECT_EQ(alignof(D3), alignof(AlignedCharArrayUnion<D3>));
   EXPECT_EQ(alignof(D4), alignof(AlignedCharArrayUnion<D4>));
   EXPECT_EQ(alignof(D5), alignof(AlignedCharArrayUnion<D5>));
   EXPECT_EQ(alignof(D6), alignof(AlignedCharArrayUnion<D6>));