[Comgr] Disable PCH probe (llvm#3440)

PCH probe is used to promote -include a.h into -include-pch a.h.pch.

Nothing guarantees that the process has read-access to a.h.pch, or that
it is in the correct format.

Related to [SWDEV-547683: hiprtcCompileProgram fails if inaccessible
hiprtc_runtime.h.pch
exists](https://ontrack-internal.amd.com/browse/SWDEV-547683)

Author: jmmartinez

amd/comgr/src/comgr-compiler.cpp

@@ -750,6 +750,11 @@ AMDGPUCompiler::executeInProcessDriver(ArrayRef<const char *> Args) {
                    "AMDGPU Code Object Manager", OverlayFS);
   TheDriver.setCheckInputsExist(false);
 
+  // We do not want the driver to promote -include into -include-pch.
+  // Otherwise, the driver may pick PCH in the wrong format, without permissions,
+  // in the process's CWD.
+  TheDriver.setProbePrecompiled(false);
+
   // Log arguments used to build compilation
   if (env::shouldEmitVerboseLogs()) {
     LogS << "    Compilation Args: ";