ANDROID: GKI: gen_gki_modules_headers update preprocessing

Since we do not enforce symbol lists to be generated using
the ABI tooling; it is possible to have the symbol list
updates with CRLF characters at the end of a line, leading
and trailining white spaces based on how they are manually
edited. The header generation script fails in this case when
it parses these symbols with CRLF or sorting order may not
be correct for symbols with trailing white spaces.

Update the preprocessing of the symbol list to remove any
carriage returns, strip any leading and trailing white spaces
in addition to the other preprocessing.

Bug: 280837072
Test: TH, manual verification
Change-Id: I4b832c28b42f196056c38fc3e2ccd517a03e13fa
Signed-off-by: Ramji Jiyani <ramjiyani@google.com>