[test] Use --sysroot instead of -B in print-multi-directory.c

[mstorsjo]

Summary

This avoids finding a similar matching GCC installation outside of the test directory tree in the surrounding environment, which would make the test fail.

[chrib]

Hi Martin,

maybe just a NIT, use --sysroot= rather than just --sysroot for consistency with other tests.

Otherwise looks good to me, thanks (adding Jonathan as I'm not sure I can accept)

[mstorsjo]

Ping @jroelofs or someone else willing to have a look

[cfe-commits]

Hi Martin,

Actually I reread the developer policy,
(https://llvm.org/docs/DeveloperPolicy.html#id13). As I contributed this
code and take responsibility for it. It seems that I can approve this patch.

So it looks OK for me, sorry for the delay,

Cheers

Christian

test/Driver/print-multi-directory.c

 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>/dev/null \
 // RUN:     -target i386-none-linux \
-// RUN:     -B%S/Inputs/multilib_64bit_linux_tree/usr \
+// RUN:     --sysroot=%S/Inputs/multilib_64bit_linux_tree/usr \
 // RUN:     -print-multi-directory \
 // RUN:   | FileCheck --match-full-lines --check-prefix=CHECK-X86-MULTILIBS %s
 
 // CHECK-X86-MULTILIBS:      32
 // CHECK-X86-MULTILIBS-NOT:  {{^.+$}}
 
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>/dev/null \
 // RUN:     -target i386-none-linux -m64 \
-// RUN:     -B%S/Inputs/multilib_64bit_linux_tree/usr \
+// RUN:     --sysroot=%S/Inputs/multilib_64bit_linux_tree/usr \
 // RUN:     -print-multi-directory \
 // RUN:   | FileCheck --match-full-lines --check-prefix=CHECK-X86_64-MULTILIBS %s
 
 // CHECK-X86_64-MULTILIBS:      .
 // CHECK-X86_64-MULTILIBS-NOT:  {{^.+$}}
 
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>/dev/null \
 // RUN:     -target arm-linux-androideabi21 \
 // RUN:     -mthumb \
 // RUN:     -B%S/Inputs/basic_android_ndk_tree \
 // RUN:     --sysroot=%S/Inputs/basic_android_ndk_tree/sysroot \
 // RUN:     -print-multi-directory \
 // RUN:   | FileCheck --match-full-lines --check-prefix=CHECK-ARM-MULTILIBS %s
 
 // CHECK-ARM-MULTILIBS:      thumb
 // CHECK-ARM-MULTILIBS-NOT:  {{^.+$}}