test-backend-ops: allow loading tests from file and parsing model operators into file (#19896)

* tests: allow loading test-backend-ops tests from json

* add error threshold based on op

* add error when file cannot be read

* add graph operator json extraction tool

* add nb parameter for non-contiguous input tensors

* fix view check

* only use view if non-contiguous/permuted, use C++ random instead of rand()

* replace internal API calls with public llama_graph_reserve call

* reduce test description length

* fix nb[0] not getting set for view

* add name to tests

* fix inplace error

* use text file instead of json

* move llama_graph_reserve function to new llama-ext header, move export-graph-ops to tests/

* fix missing declaration

* use pragma once

* fix indent

* fix Windows build

tests/CMakeLists.txt

@@ -260,6 +260,7 @@ endif()
 set(LLAMA_TEST_NAME test-mtmd-c-api)
 llama_build_and_test(test-mtmd-c-api.c)
 target_link_libraries(${LLAMA_TEST_NAME} PRIVATE mtmd)
+unset(LLAMA_TEST_NAME)
 
 # GGUF model data fetcher library for tests that need real model metadata
 # Only compile when cpp-httplib has SSL support (CPPHTTPLIB_OPENSSL_SUPPORT)
@@ -284,4 +285,5 @@ target_link_libraries(${TEST_TARGET} PRIVATE llama)
 llama_build_and_test(test-alloc.cpp)
 target_include_directories(test-alloc PRIVATE ${PROJECT_SOURCE_DIR}/ggml/src)
 
-
+llama_build(export-graph-ops.cpp)
+target_include_directories(export-graph-ops PRIVATE ${PROJECT_SOURCE_DIR}/ggml/src)