Function argument in *probes_inl.h should follow snake_case naming convention

The primary motivation is that the function argument is not following
the snake_case naming convention. As per current implementation
function argument names in *probes_inl.h follow |paramFoo| naming
convention. This CL modify build_param_name() in
make_instrumenting_probes.py to rename function argument names to adopt
|param_foo| naming convention.

Bug: 936684
Change-Id: Idb63f1e6b78c98bb1830e74165b6cc69a8515a94
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1503179Reviewed-by: Kent Tamura <tkent@chromium.org>
Commit-Queue: Abhijeet Kandalkar <abhijeet@igalia.com>
Cr-Commit-Position: refs/heads/master@{#638006}

third_party/blink/renderer/build/scripts/make_instrumenting_probes.py

@@ -165,7 +165,7 @@ class Parameter(object):
 
 
 def build_param_name(param_type):
-    return "param" + re.match(r"(const |scoped_refptr<)?(\w*)", param_type).group(2)
+    return "param_" + NameStyleConverter(re.match(r"(const |scoped_refptr<)?(\w*)", param_type).group(2)).to_snake_case()
 
 
 def load_config(file_name):