[libc] add dependencies to generic sqrt tests

[michaelrj]

Summary

This adds dependencies on the corresponding sqrt function to each
generic sqrt test. This is so that on platforms that don't support the
math functions, the tests are not run.

[sivachandra]

IMHO, this is not correct - you are introducing an artificial dependency and your expectation will break in future when sqrt functions are actually available say via inline assembly. You should rather just disable these tests for targets they are not ready for.

libc/test/src/math/CMakeLists.txt

 add_fp_unittest(
   generic_sqrtf_test
   NEED_MPFR
   SUITE
     libc_math_unittests
   SRCS
     generic_sqrtf_test.cpp
   DEPENDS
+    libc.src.math.sqrtf
     libc.src.__support.FPUtil.fputil
     libc.src.__support.FPUtil.generic.sqrt
   COMPILE_OPTIONS
     -O3
 )
 
 add_fp_unittest(
   generic_sqrt_test
   NEED_MPFR
   SUITE
     libc_math_unittests
   SRCS
     generic_sqrt_test.cpp
   DEPENDS
+    libc.src.math.sqrt
     libc.src.__support.FPUtil.fputil
     libc.src.__support.FPUtil.generic.sqrt
   COMPILE_OPTIONS
     -O3
 )
 
 add_fp_unittest(
   generic_sqrtl_test
   NEED_MPFR
   SUITE
     libc_math_unittests
   SRCS
     generic_sqrtl_test.cpp
   DEPENDS
+    libc.src.math.sqrtl
     libc.src.__support.FPUtil.fputil
     libc.src.__support.FPUtil.generic.sqrt
   COMPILE_OPTIONS
     -O3
 )
 
 add_fp_unittest(
   remquof_test