[esp32c6] Add test base file and platformio env (#8973)

platformio.ini

@@ -323,6 +323,17 @@ build_flags =
     ${flags:clangtidy.build_flags}
     -DUSE_ESP32_VARIANT_ESP32C3
 
+;;;;;;;; ESP32-C6 ;;;;;;;;
+
+[env:esp32c6-idf]
+extends = common:esp32-idf
+board = esp32-c6-devkitc-1
+board_build.esp-idf.sdkconfig_path = .temp/sdkconfig-esp32c6-idf
+build_flags =
+    ${common:esp32-idf.build_flags}
+    ${flags:runtime.build_flags}
+    -DUSE_ESP32_VARIANT_ESP32C6
+
 ;;;;;;;; ESP32-S2 ;;;;;;;;
 
 [env:esp32s2-arduino]