ignore PHP vendor/ folder

Polishing the new C# API

remove php composer.lock file

Validate that headers contain legal bytes

Add 'installDist' task to grpc-java Docker build

Eliminate need for SIGPIPE handling

Cleanup unlock() a little

This will allow us to not run Gradle every time we run an integration
test.

Fix server side call finalization when connection is closed.

update php composer.lock

more division of logs to make it easier to analyze test results.

Test log

Pin the version of rubocop used in grpc.gemspec

Added support for important mark (!) analysis.

For example, an input of
GRPC_LAT_PROF 1316908107613.015869 0x7fd35f7fe700 { 205 (nil)
src/core/iomgr/tcp_posix.c 1
GRPC_LAT_PROF 1316908107614.015869 0x7fd35f7fe700 { 205 (nil)
src/core/iomgr/tcp_posix.c 2
GRPC_LAT_PROF 1316908107615.015869 0x7fd35f7fe700 ! 999999 (nil)
src/core/iomgr/tcp_posix.c 3
GRPC_LAT_PROF 1316908107616.015869 0x7fd35f7fe700 } 205 (nil)
src/core/iomgr/tcp_posix.c 4
GRPC_LAT_PROF 1316908107617.015869 0x7fd35f7fe700 ! 999999 (nil)
src/core/iomgr/tcp_posix.c 5
GRPC_LAT_PROF 1316908107618.015869 0x7fd35f7fe700 } 205 (nil)
src/core/iomgr/tcp_posix.c 6

results in

tag 50%/90%/95%/99% us
205 5.00/5.00/5.00/5.00

Important marks:
================
999999 @ src/core/iomgr/tcp_posix.c:3
205 { (src/core/iomgr/tcp_posix.c:1):        2.000 us
205 { (src/core/iomgr/tcp_posix.c:2):        1.000 us
205 } (src/core/iomgr/tcp_posix.c:4):       -1.000 us
205 } (src/core/iomgr/tcp_posix.c:6):       -3.000 us

999999 @ src/core/iomgr/tcp_posix.c:5
205 { (src/core/iomgr/tcp_posix.c:1):        4.000 us
205 } (src/core/iomgr/tcp_posix.c:6):       -1.000 us

add command for the rest of PHP interop test

Added important (!) profiling mark.

It's meant to have a special status in the analysis, whereby latencies
from important marks to all their enclosing BEGIN ({) and END (})
markings will be measured.

Optimize a few core routines