[XRay][compiler-rt][NFC] Expand the PIC test case for XRay

Summary:
Here we add a build with -ffunction-sections -fdata-sections and
-Wl,--gc-sections to ensure that we're still able to generate XRay
traces.

This is just adding a test, no functional changes.

Differential Revision: https://reviews.llvm.org/D36863

llvm-svn: 311145