Perform SQL comment scanning with a manual parser

SQL strings are scanned to find the (first) SQL command and to
characterize the statement.  This change replaces a regular expression
parser with a hand-crafted parser.

Custom unit tests indicate that the new parser is 10x faster than the
regex implementation.  Native memory allocation done by the Java
Matcher class is eliminated.

Additional unit tests have been added to test the scanner.

Test : atest
 * FrameworksCoreTests:android.database

Flag: android.database.sqlite.simple_sql_comment_scanner
Bug: 329118560

Change-Id: I3124dd7f57147607a07b42cfa711e54a81348b10