[SanitizerCoverage] add weak definitions for the load/store callbacks.

[kcc]

Summary

Add weak definitions for the load/store callbacks.

This matches the weak definitions for all other SanitizerCoverage
callbacks.

[vitalybuka]

it breaks some asan tests https://reviews.llvm.org/harbormaster/unit/view/4420740/

[kcc]

needed to add the same callbacks in more places.
Now the tests pass.

compiler-rt/lib/sanitizer_common/sanitizer_coverage_libcdep_new.cpp

 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_const_cmp2, void) {}
 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_const_cmp4, void) {}
 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_const_cmp8, void) {}
 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_switch, void) {}
 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_div4, void) {}
 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_div8, void) {}
 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_gep, void) {}
 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_pc_indir, void) {}
+SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_load1, void){}
+SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_load2, void){}
+SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_load4, void){}
+SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_load8, void){}
+SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_load16, void){}
+SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_store1, void){}
+SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_store2, void){}
+SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_store4, void){}
+SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_store8, void){}
+SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_store16, void){}
 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_8bit_counters_init,
                              char* start, char* end) {
   __sancov::SingletonCounterCoverage::Cov8bitCountersInit(start, end);
 }
 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_bool_flag_init, void) {}
 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_pcs_init, const uptr* beg,
                              const uptr* end) {
   __sancov::SingletonCounterCoverage::CovPcsInit(beg, end);