utils: Supress GCC array-bound warning (#6807)

closes https://github.com/KhronosGroup/SPIRV-Tools/issues/6805

We do this same-ish thing in `source/utils/hex_floats.h` 

I looked, there was no changes to `timer.h` or `pass_manager.cpp` so not
sure what this suddenly is happening, seems to just be something the
latest GCC is catching

source/util/timer.h

diff --git a/source/util/timer.h b/source/util/timer.h
index 0808311..e9a3a59 100644
--- a/source/util/timer.h
+++ b/source/util/timer.h
@@ -23,6 +23,11 @@
 #include <cassert>
 #include <iostream>
 
+#if defined(__GNUG__)
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Warray-bounds"
+#endif
+
 // A macro to call spvtools::utils::PrintTimerDescription(std::ostream*, bool).
 // The first argument must be given as std::ostream*. If it is NULL, the
 // function does nothing. Otherwise, it prints resource types measured by Timer
@@ -382,6 +387,10 @@
 }  // namespace utils
 }  // namespace spvtools
 
+#if defined(__GNUG__)
+#pragma GCC diagnostic pop
+#endif
+
 #else  // defined(SPIRV_TIMER_ENABLED)
 
 #define SPIRV_TIMER_DESCRIPTION(...)